EP1413456B1 - Plastic body, which is provided in the form of a film, for example, a transfer film or laminate film or which is provided with a film of this type, and method for producing a multicolour image on or in a plastic body of this type - Google Patents

Abstract

A plastic article consists of foil, e.g. transfer foil, hot embossing foil, or laminating foil or is provided with a foil and includes a colorant mixture of not less than 3 different components, each of which is a pigment or other colorant and can be bleached with a laser under conditions specific for the component. Each of the 3 components cannot be (substantially) bleached under the specific laser conditions for the other components. An Independent claim is also included for the production of a multicolored image on or in the article by bleaching a point with laser radiation in stages under conditions specific for (1) only one of the 3 components and (2) only one of the other components.

Description

The invention relates to a plastic body as a foil, e.g. Transfer film, in particular hot stamping film, or laminating formed or provided with such a film, according to the preamble of claim 1 and a method for producing a multi-color image on or in such a plastic body.

From WO 96/35585, which forms the closest prior art, various embodiments of Kunststoffkörpem namely massive body or coatings are known, each containing a mixture of different pigments. In the exemplary embodiments described there, the pigment mixture is composed of three pigment components, namely a yellow pigment, a magenta pigment and a cyan pigment. By laser treatment color marking is done on the plastic body. The color marking is produced by bleaching the pigments with the laser treatment. The laser conditions are each set specifically with variations of the wavelength to obtain certain colors. The specific wavelength used in each case is determined beforehand by light absorption measurements on the pigments, specifically the absorption wavelength in the absorption maximum of the pigment is determined in each case. In each case pigments are used which have only a single absorption maximum. This is to ensure that in the laser treatment, a color is obtained that corresponds to the laser light and the duration of the laser treatment and the intensity of the laser light for each color can have the same value. In the described embodiments with the pigment mixture of yellow pigment, Magenta pigment and cyan pigment are used for laser treatment violet laser light at wavelength 430 nm, blue laser light at wavelength 470 nm, yellow laser light at wavelength 575 nm and designated as orange laser light at wavelength 650 nm. In this way, to be produced by the laser treatment by appropriate adjustment of the laser wavelength with otherwise the same laser conditions different color marks on the plastic body. The colors are created by a complex mixture of the same bleached pigments at the respective laser wavelength. Disadvantage is that no method is given, with which all colors could be generated.

In WO 98/19868 a correspondingly working method for the production of color markers is described in which, however, special yellow, magenta and cyan pigments are used, namely, in a first step can be activated by UV light and only in a subsequent second step to be bleached.

In the non-prepublished DE 199 55 383 A2 a method for the production of color markings by laser treatment is described, which works using a 2-coordinate beam deflector with focusing, wherein a special mirror device is used. The body to be marked has a mixture of cyan pigment, magenta pigment and yellow pigment, these pigments being selectively bleached by red laser light, green laser light and blue laser light, respectively. It is essential that this method does not provide for a film, preferably a multilayer film, to be used as a transfer film or as a laminating film or a film applied to a substrate.

From WO 94/12352 is also known, on a plastic body containing a pigment mixture and may be formed as a solid body or as a coating by laser treatment with different wavelength colorful color marks to produce. The color formation occurs because the pigments change their color by color change during the laser treatment. The laser conditions are chosen at random. A method to selectively generate any colors is not given here. The number of colors produced in this way is very limited.

From EP 0 327 508 a method is known in which a laser-sensitive dye A and a laser-insensitive dye B are contained in two separate superimposed layers or alternatively in a common layer and bleached by laser treatment of the dye A, while the dye B is not or only a little bleached. With the laser treatment, a color mark is obtained. The method does not provide for variation of laser conditions with respect to wavelength, and it is only a monochrome marker, i. to get a maximum two-color image.

A method is known from EP 0 190 997 B1, in which an additive is contained in a plastic layer formed as a coating of a metal leaflet or in a plastic plate, which is to discolor during laser treatment, either by color change from one color to another or conversion in black. It is not possible to create color markings with different colors.

DE 37 38 330 A1 discloses a laser marking method for use on surfaces with pigment coating, wherein pigments of the pigment coating change their internal molecular structure at different temperatures and provide different colors. With the laser irradiation, the specific surface temperatures are locally achieved, whereby colored laser markings are obtained.

GB 2 240 948 A also describes laser marking of ID cards. Laser marking is done here by removing different layers of paint. The resulting laser marking appears as a colored mark.

DE 41 31 964 A1 describes laser inscriptions of a multilayer film with metal layer and hologram structure. The labeling is done by partially destroying the hologram-bearing metal layer.

From EP 0 420 261 a hot stamping foil with hologram structure is known, which is individualized by means of laser treatment for the purpose of protection against counterfeiting. By means of the laser beam, a change of material or color or a removal of partial regions in the layer structure of the film takes place. A multi-color marking is not provided here.

From EP 0 416 664 B1 it is known to produce black markings by laser marking in plastic bodies or film layers. The marking is formed by laser-induced blackening of the laser-sensitive component molybdenum sulfide contained in the plastic.

DE 44 10 431 describes a method by which personal data is introduced by laser inscription on an identity card, wherein the identity card has a copy protection element applied in the transfer method. In laser marking, a code in the form of a number series is introduced by inserting a part of the number series in the copy protection element and a further part of the number series in a subsequent area of the identification card. The laser marking takes place via local demetallization in the metal layer of the copy protection element or by blackening of the treated area of the identification card.

EP 0 219 011 B1 describes a special method for the laser marking of identity cards. In this method black markings are introduced in different transparent layers of the card by means of the laser. In the interacting transparent layers paralaxe images are obtained in this way.

From DE 195 22 397 A1 it is known to produce bright inscription by laser treatment of pigments containing plastic layers. This is done by laser bleaching the pigments contained.

Further, it is e.g. from EP 0537668 and DE 8130861 U1 known to ablate layers by laser treatment in the layer structure of transfer films, so as to obtain labels.

Moreover, it is e.g. from EP 0741370 B1, DE 4333546 A1 or US 4,911,302 known to produce marks by laser treatment of laminated bodies by laser-induced melting of the material to then transfer these labels still in the molten state to another body.

The invention has for its object to provide a plastic body of the type mentioned on or in the laser treatment over several different color markers are selectively generated, preferably markings can be generated in any color in the manner of a full-color image. In addition, the invention has for its object to provide a method for producing such a body.

This object is achieved by the invention with a plastic body according to claim 1 or with a method according to claim 9.

The plastic body has a mixture with at least three components, each of these components being in each case a colorant, for example a pigment or another colorant. The pigments are usually insoluble, preferably inorganic colorants. Other colorants are, for example, organic colorants. These are mostly soluble. Mixtures can be used which have as pigments exclusively pigments or exclusively other colorants or pigments and other colorants. The colorants, which thus form the components of the mixture, are referred to below as components. It is essential that one or more of the components is bleachable by means of laser under each specific for the component laser conditions or are. That is, for bleaching the first component, a first laser condition is provided, for example, a first specific laser wavelength; For bleaching the second component, a second laser condition, for example a second specific laser wavelength, is provided and for bleaching the third component a third one is provided Laser condition, eg a third specific laser wavelength. These specific laser conditions or laser wavelengths used for bleaching the various components are different from each other. They are further selected such that only one component or preferably only one component is bleachable under the laser conditions specific to one component, for example the specific laser wavelength, and the remaining components are not or substantially not bleachable. This makes it possible to bleach specifically only one component in the laser treatment in one step and to leave the others unchanged.

When using a three-component mixture, therefore, the color of the body is formed by the three components before the first step. After the laser treatment of the first step, the color of the body at the treated site is formed by the two components not bleached during the laser treatment of the first step and optionally additionally by the residual color of the component more or less bleached depending on the treatment in the first step. Preferably, color formation is achieved by subtractive mixing of those in the plastic body, i. mixed in the plastic layer or throughout the solid plastic body present components. The various components can be mixed in a layer closely adjacent to each other or in a multi-layered form one above the other.

The method for producing a multi-color image on or in such a plastic body provides that in a first step by laser irradiation of a body of the plastic body for one of the example (three) components specific laser conditions, only the one component is bleached and that in a second step Laser irradiation of the same body of the body for another of the (three) component specific laser conditions only this further component is bleached. In the first step, the (two) further non-bleached components thus remain in addition to the bleached first component, so that the color is thus formed by these (two) non-bleached components, optionally with incomplete degree of bleaching of the first component in addition to the residual color of only more or less bleached first component. After the second step, in which the second component is bleached, if one has originally used a 3-component mixture, only one component remains, so that then the color is formed only by this remaining component. This is true in the case where the remaining components have been completely bleached in the previous steps. Otherwise, ie, if the degree of whitening of the first component is not complete in the first step and if the degree of whitening of the second component in the second step is not complete, the color after the second step is additionally colored by the residual color of the first and second bleaches bleached only more or less in the first and second steps Components formed.

Further, as a possible third step, the laser treatment of the same location of the body for the third component, i. the previously unbleached component is provided, the same location of the plastic body at laser conditions specific to that third component, e.g. specific laser wavelength, only this third component is bleached. After this third step, all three components are bleached at the point in question or more or less bleached depending on the degree of bleaching. This point thus appears colorless or tinted depending on a possible colored background layer or any other components in the plastic body or in the same layer of the plastic body, in the limiting case white background white.

Furthermore, any further steps are provided, in each of which one or more further components is or will be bleached with specific laser conditions. It is preferably provided that, generally in an nth step, only the nth component is bleached by laser irradiation of the same location of the plastic body for only another of n components.

Depending on the choice of the components and the specific laser conditions can also be provided that at least one of the components has a color change in the laser irradiation.

In the case of laser treatment in the individual steps, it is provided in each case that the degree of bleaching or color change to be achieved in the laser irradiation is adjusted by controlling the laser conditions, in particular the laser wavelength, the laser intensity and / or the irradiation time.

The laser conditions used in each of the individual steps are preferably experimentally determined and / or optimized before carrying out the method by means of experiments with the individual components. The criterion in the selection of the laser conditions is preferably the bleaching result to be achieved. The selection of the laser conditions used in the individual steps can be such that the component absorbs light at the wavelength of the laser light used for bleaching by the component at this wavelength an absorption maximum, preferably one of several absorption maxima or preferably its single or largest Has absorption maximum. However, the selection can also be made so that the component absorbs light at the wavelength of the laser light used for bleaching, but the component at this wavelength has no absorption maximum, but this wavelength is outside the absorption maximum or outside the absorption maxima of the component.

• a) cyan+magenta+gelb schwerz
• b) cyan+magenta blau
• c) cyan+magenta grün
• d) gelb+magenta rot

In order to be able to work with a pigment mixture with relatively few pigment components and to be able to produce as many as possible, preferably all colors, it is advantageous if one component is a cyan pigment and / or one component is a magenta pigment and / or one component is a yellow pigment is. Preferably, a cyan pigment, a magenta pigment and a yellow pigment are contained in the pigment mixture. In particular embodiments, the pigment mixture is a mixture with only three pigment components, preferably cyan pigment, magenta pigment and yellow pigment. With these three colors, all colors can be created by subtractive mixing. By the specific bleaching of the individual pigment components in the individual steps, blue can be produced, for example, in the first step, if in this first step only or preferably only the Yellow pigment component, or green may be produced in the first step if in said first step only or preferably only the magenta pigment component is bleached, or red may be generated in the first step if in said first step only or preferably only the cyan pigment component bleaches becomes. In the second step, the color cyan, magenta or yellow can then be produced by bleaching another of the remaining pigment components not bleached in the first step, ie if blue has been produced in the first step and therefore cyan and magenta have not been bleached in the first step In the second step, the color cyan can be produced by bleaching the magenta component in the second step. The generation of the other colors is done in a similar way, because it applies to the subtractive color mixing:

• a) cyan + magenta + yellow heavy
• b) cyan + magenta blue
• c) cyan + magenta green
• d) yellow + magenta red

The color mixture a) is present before the laser treatment, ie before the first step. The plastic body appears black or gray. The color mixture b) or c) or d) is present after the first step, ie the plastic body has a blue or green or red color marking at the location at which the laser treatment is carried out in the first step. After the second step, that is, when the laser treatment of the second step has been carried out at the same place in the second step, the color mark at that location of the plastic body is cyan or yellow or magenta, depending on which of the two in the first step in this second step, unbleached pigment components have not been bleached. In order to obtain a colorless or transparent marking at this point in the third step, the third step is then to be carried out at this same point, in which the remaining not yet bleached pigment is bleached with the respective pigment-specific laser conditions.

In this way, a color marking in any desired color can be generated at each point by successive laser treatment at this same location. It can be treated in this way consecutively adjacent locations of the plastic body and so on the plastic body by adjacent color markers a multi-color image, preferably a so-called full-color image can be generated.

Instead of the pigment mixture described above with the pigment components cyan pigment, magenta pigment and yellow pigment, it is also possible to use a corresponding colorant mixture with non-pigment colorants, i. a colorant mixture of cyan colorant, magenta colorant and yellow colorant as components. In this case, it is possible to work in the same way, with the laser conditions specific to the respective colorants being used in the individual steps.

For laser treatment, pulsed frequency-multiplied solid-state lasers, optical parametric oscillators (OPO's) and pulsed UV lasers (for example excimer lasers) are preferably used in the various systems. In the laser treatment, the intensity and / or the pulse duration of the laser radiation is preferably set such that a maximum bleaching result or a maximum color change occurs without any recognizable material damage to the plastic body. The method can be used on solid plastic bodies and also on transfer foils, in particular hot stamping foils, or on laminating foils. The use of transfer or laminating films has advantages in that these films can be applied to a variety of materials, e.g. Metals, wood, etc. can be applied to decorate any body. With the films results in only low colorant or pigment requirements, since the colorants or pigments must then be present only in a thin layer. With the use of foils it is also possible to coat any large bodies only locally, z, B. by printing process.

In the laser treatment, energy densities are preferably applied between 0.05 and 0.5 J per cm ² with a pulse duration of 5 to 20 ns, the Bleaching result can also be determined by the pulse rate. The laser-sensitive layer with the pigment mixture can be present on the transfer or laminating film over the entire area, but also only in certain areas.

Figuren 1 bis 5

Schnittdarstellungen von verschiedenen Heißprägefolien jeweils mit lasersensitiver Schicht.

Figuren 6 bis 10

Schnittdarstellungen verschiedener Laminierfolien jeweils mit lasersensitiver Schicht.

In the following preferred embodiments are explained in more detail with reference to the accompanying figures.
Show it:

FIGS. 1 to 5

Sectional views of different hot stamping foils, each with a laser-sensitive layer.

FIGS. 6 to 10

Sectional views of different laminating films each with a laser-sensitive layer.

The foils shown in FIGS. 1 to 5 are hot stamping foils. The hot stamping foil in FIG. 1 comprises a carrier film 1, a release layer 2, a protective layer 3, a laser-sensitive layer 4, a background layer 5 and an adhesive layer 6.

The carrier film 1 is preferably a polyester film having a thickness of 6 to 100 μm, preferably a thickness of 19 to 38 μm. On this carrier film 1, the layers 2 to 6 are arranged one above the other. They are applied in the production of the hot stamping foil according to known methods.

The release layer 2 is a release layer. It is preferably in the form of a layer that becomes soft during heat development and, when the hot stamping film is applied to the substrate, permits the detachment of the further layers from the carrier film 1. The peel layer 2 generally has a thickness of at most 1 μm.

The protective layer 3 is formed as a protective lacquer layer . It is a transparent varnish layer with the task of the free surface of the decorated with the hot stamping foil object against mechanical damage and Protect chemical agents to a large extent. The layer thickness is preferably between 1 and 2 μm.

The laser-sensitive layer 4 is designed as a so-called first colored lacquer layer . This is a varnish layer colored by pigments or other colorants and having a thickness of preferably 3 to 10 .mu.m. The pigments or the other coloring systems or colorants of this color coat layer are selectively bleachable by means of a laser beam whose wavelength is preferably in the visible range and / or changeable by color change in color. The pigment concentration of this lacquer layer 4 is preferably between 3 and 15% based on solids. The binder system of this lacquer layer 4 must not be optically changed by the action of the laser, so that only a colored contrast marking is formed at the irradiated points without any noticeable damage to the foil. The film is not damaged on the surface or on the inside.

The background layer 5 is formed as a so-called second color coat layer. This layer is colored differently than the laser-sensitive layer 4. The layer 5 is, for example, white or ivory when the laser-sensitive layer 4 is black or gray. The layer 5 serves primarily as a light backup layer for the colors generated in the laser-sensitive layer 4 by laser radiation. The layer thickness of the layer 5 is preferably 5 to 20 microns or 15 to 20 microns.

It is possible to provide the background layer 5 - as well as the laser-sensitive layer 4 - not over the entire surface of the hot stamping foil and thus not over the entire surface to be decorated in the same color position. The layers 4 and 5 can rather individually - and thus also different - be composed of different colored areas.

The adhesive layer 6 is a conventional adhesive layer of a thickness of about 1 to 10 .mu.m in the case of transfer films, the adhesive layer for a hot stamping film being composed in such a way that it becomes tacky only when heat is applied accordingly.

The layers 2 to 6 can be produced according to the following recipes:

Release Layer 2 (Release Layer):

toluene 99.5 parts Ester wax (dropping point 90 ° C) 0.5 parts

Protective layer 3 (protective lacquer layer):

methyl ethyl ketone 61.0 parts Diaketonalkohol 9.0 parts Methyl methacrylate (Tg = 122 ° C) 18.0 parts Polyethylene dispersion (23% in xylene) (softening point 140 ° C) 7.5 parts High molecular weight dispersing additive (40%, amine number 20) 0.5 parts Extender (aluminum silicate) 4.0 parts

Laser-sensitive layer 4 (first color coat layer):

methyl ethyl ketone 34.0 parts toluene 26.0 parts ethyl acetate 13.0 parts Cellulose nitrate (low viscosity, 65% in alcohol) 20.0 parts Linear polyurethane (mp> 200 ° C) 3.5 parts High molecular weight dispersing additive (40%, amine number 20) 2.0 parts For example: Pigment Blue 15: 4 0.5 parts Pigment Red 57: 1 0.5 parts Pigment Yellow 155 0.5 parts

Background layer 5 (second color coat layer):

methyl ethyl ketone 40.0 parts toluene 22.0 parts Ethylene-vinyl acetate terpolymer (mp = 60 ° C) 2.5 parts Polyvinyl chloride (Tg: 89 ° C) 5.5 parts Polyvinyl chloride (Tg: 40 ° C) 3.0 parts Dispersing additive (50%, acid number 51) 1.0 parts Titanium dioxide (d = 3.8-4.2 g / cm ³ ) 26.0 parts

Adhesive layer 6:

methyl ethyl ketone 55.0 parts toluene 12.5 parts ethanol 3.5 parts Polyvinyl acetate (softening point 80 ° C) 6.0 parts Butyl / methyl methacrylate (Tg: 80 ° C) 8.0 parts Ethyl methacrylate resin (Tg: 63 ° C) 3.0 parts Methacrylate copolymer (Tg: 80 ° C) 5.0 parts Unsaturated polyester resin (softening point 103 ° C) 3.5 parts silica 3.5 parts

Instead of this hot stamping foil and another transfer film can be used. It may have the appropriate structure as the hot stamping foil described.

Transfer foils - in this case, hot stamping foils in this case - are preferably applied in a conventional manner to a substrate in such a way that the adhesive layer 6 faces the substrate surface. The adhesive layer 6 then forms an adhesive bond with the substrate surface during hot stamping. The carrier film 1 is then - after the heat under action during hot stamping softening of the release layer 2 - deducted. In the case of the hot stamping foil thus applied to the substrate surface, the protective layer 3 then forms the upper surface of the stamping foil facing away from the substrate.

The hot stamping foils illustrated in FIGS. 2 to 4 have a background layer of a different design than the foil in FIG. 1. In the example in FIG. 2, the background layer is formed as a reflection layer 5r. In a special case, the reflection layer is designed as a metallic reflection layer. The reflection layer can be transparent or partially transparent for certain spectral ranges. It can have a higher refractive index than the other layers and therefore has increased light reflection. In the example in FIG. 3, a layer 5c is provided as an additional lacquer layer, which is preferably transparent. Furthermore, a reflection layer 5r is provided, which has a diffraction or hologram structure 5b in regions. In the exemplary embodiment in FIG. 3, this structure 5b is formed as a component of the lacquer layer 5c and the adhesive layer 6 as well as the intermediate layer. Alternatively or additionally, a diffraction structure can also be formed as a constituent of the lacquer layer 5c and / or the laser-sensitive lacquer layer 4 and / or the adhesive layer 6. The diffraction structure can in these cases as shown partially, but also be formed as a continuous layer.

In the example in FIG. 4, a printed image 5d is arranged in the background layer 5c in a limited area and a limited laser-sensitive area 4a is arranged laterally offset in the laser-sensitive layer.

FIG. 5 shows a hot stamping foil with a modified layer structure. The layer structure is similar to that in FIG. 3, but the sequence of the layers is modified in such a way that the laser-sensitive layer 4 is arranged on the side of the reflection layer 5 facing the substrate. The layers are stacked in the following order:

A carrier film 1, a release layer 2, a protective layer 3, an intermediate layer 5c, a reflective layer 5, a laser sensitive layer 4, a background layer 7 and an adhesive layer 6. In the adjacent regions of the laser sensitive layer 4, reflective layer 5 and intermediate layer 5c is a Diffraction structure 5b formed. It can be designed as a diffraction grating. Alternatively, the structure 5b may also be formed as a hologram structure. In the illustrated embodiment in Fig. 5, the diffraction structure 5b is formed in the production of the film by the diffraction structure is first impressed in the intermediate layer 5c, then the reflection layer 5r, z. B. is applied by vapor deposition. The reflection layer 5 is formed in the portions outside the diffraction structure as a smooth reflection layer 5r. It preferably has a layer thickness of <1 μm. It is transparent or partially transparent at certain viewing angles, at least for certain spectral ranges. After the application of the reflection layer 5r, the laser-sensitive layer 4 is applied. The diffraction structure 5b thus produced is formed in the adjoining areas of the layers 5c and 4. When considering the diffraction structure, varying optical effects result depending on the illumination and viewing angle.

5a, the layers are in the following order: carrier layer 1, release layer 2, protective layer 3, laser-sensitive layer 4, reflection layer 5r, Laser-sensitive layer 4, additional resist layer 7 and adhesive layer 6. The formed on both sides of the reflective layer 5r laser-sensitive layers 4 may be formed identically, ie, the reflection layer is then arranged in this laser-sensitive overall layer. However, the laser-sensitive layers can also be designed differently. In mutually adjacent regions of the laser-sensitive layers 4 and the reflection layer 5r, a diffraction structure 5b is formed. Alternatively, the structure 5b may also be formed as a hologram structure. Increased security against forgery results in this embodiment in that two laser-sensitive layers adjoin the diffraction or hologram structure, which may be identical or different. The lacquer layer 7, which is optional, is in this case designed as a transparent layer or as a light backup layer. Alternatively, the lacquer layer 7 and the adhesive layer 6 can be dispensed with and the second laser-sensitive layer 4 shown in FIG. 5 a below the reflection layer 5 r can be formed as a laser-sensitive adhesive layer.

In the case of the film in FIG. 5b, the layers are in the following order:

Carrier film 1, release layer 2, laser-sensitive layer 4, additional lacquer layer 5c, reflective layer 5r, adhesive layer 6. The layers 5c and 6 may be formed of identical material or different material. In the case of the laser-sensitive layer 4, this exemplary embodiment is a protective lacquer layer which is laser-sensitive in that it contains the relevant comparable pigments. In the adjoining areas of additional paint layer 5c, reflective layer 5r and adhesive layer 6, a diffraction structure is formed. It can be designed as a diffraction grating. Alternatively, the structure 5b may also be formed as a hologram structure.

After the transfer film, in the present case embossing film, is applied to the substrate, the laser treatment is carried out in order to produce transparent and / or colored markings in the laser-sensitive layer 4. In order to produce a specific marking, preferably color marking, at a specific position in the laser-sensitive layer 4, this point is irradiated with laser radiation.

In the case of the laser treatment of a film having the layer structure according to FIG. 5, the laser irradiation takes place through the reflection layer including the diffractive structure 5b. The laser beam is preferably directed perpendicular to the film plane from above. The reflection layer 5r is permeable to the laser radiation, in particular in the case of perpendicular irradiation. The lattice or hologram structure 5b of the layer forming the reflection layer 5r in the remaining area is also permeable to the laser radiation, but the radiation can be reflected more or less also and partly at the diffraction structure. The laser-sensitive layer 4 which is formed under the layer forming the reflection layer 5r in the remaining area still within the diffraction structure 5b and below is changed by the action of the laser by a color change by bleaching at the specific location.

The bleaching process, as it proceeds in the respective laser-sensitive layer in the illustrated embodiments, will be described below.

In bleaching, in a first step, a blue or green or red color mark is produced by irradiating that spot with a particular laser wavelength that bleaches a particular pigment component.

To produce the color blue, only the yellow pigment component must be bleached. For this purpose, blue laser light is used. Bleaching requires a certain minimum intensity. Furthermore, a certain pulse duration must not be exceeded. In order to obtain a green color marking in the first step, only the magenta pigment component may be bleached. For this purpose, green laser light is used. To get a red color mark in the first step, only the cyan pigment component should be bleached. For this purpose, red laser light is used.

In order to produce at this point a color marking in the color cyan or magenta or yellow, this point is laser-treated in a second step, with a laser wavelength with which one of the not yet bleached at this point pigment components is bleached. If in the first step a blue Color marking is generated, at this point the cyan pigment component and the magenta pigment component are unbleached. To make the color cyan at this point, the magenta pigment component must be bleached in this second step. This is done with green laser light. This results in a cyan mark at this point.

If, in the second step, a magenta mark is to be obtained instead of this cyan mark, the blue mark produced in the first step must be treated with red laser light. As a result, the cyan pigment is bleached at this point, so that the magenta pigment remains unbleached at this point. This results in the magenta marking at this point.

In a corresponding manner, a green color marking produced in the first step, which is formed from unbleached cyan pigment and yellow pigment remaining there, can produce a cyan-colored marking or a yellow-colored marking by treatment with blue laser light or red laser light.

In a corresponding manner, a red color marking produced in the first step can be converted into a yellow or magenta marking in the second step by laser treatment in the second step with green laser light or blue laser light.

In order to obtain a transparent spot at the location treated in the first and second steps, ie to obtain a white spot when the background layer 5 is white, in a third step this spot must be treated with a laser beam whose wavelength is adjusted that the pigment component remaining unbleached at this point after the second step is bleached, ie the yellow color marking must be bleached with blue laser light, the magenta mark with green light and the cyan mark with red laser light.

In the same way, further adjacent points are then treated in the laser-sensitive layer 4 in order to produce further color markings in the layer 4 of the stamping foil. In this way, a full-color image can be produced.

Laser treatment can also be used to produce color markers or a full-color image in the colorant or the colorants in the laser-sensitive layer by color change. The laser treatment can be carried out in a corresponding manner with successive process steps. As a colorant, i. Coloring substances are pigments in question. These are usually insoluble and are usually inorganic substances. As a colorant but also mostly soluble, organic colorants in question. The color change takes place in each case under specific laser conditions, which are then used in the laser treatment in the individual steps.

Alternatively, the laser treatment of the transfer film for producing the color markings can also take place before the application of the film, in particular if the protective layer 3 is formed as a layer which is not or only partly transparent to laser radiation or a layer which is not transparent for laser radiation in the specific wavelength range or an additional UV-absorbing protective layer is provided. The laser treatment is then performed prior to application of the film by exposing the laser beam to the back of the film, i. is directed to the background layer 5 and the adhesive layer 6 and thus the laser-sensitive layer 4 is thus treated from the other side to produce the color markings in the same way. The background layer 5 and the adhesive layer 6 are transparent or at least partially transparent for the laser radiation in question in these applications.

In a corresponding manner, color markings can also be produced in laminating films. Such laminating films are shown in FIGS. 6 to 10. The laminating film in FIG. 6 comprises a so-called overlay film 30, an optional intermediate layer 31, a laser-sensitive layer 40, a background layer-forming intermediate layer 50, which is also optional, and an adhesive layer 60, which is also optional. During the lamination process, the laminating film with the Adhesive layer 60 of the substrate surface facing applied to the substrate. Via the adhesive layer 60, an adhesive bond with the substrate surface is formed. The overlay film 30 then forms the upper protective layer whose surface facing away from the substrate forms the outer surface of the film. The overlay film 30 therefore remains applied after the application of the laminating film. It corresponds to the protective layer 3 of the embossing foil in FIG. 1. The laser-sensitive layer 40 corresponds to the laser-sensitive layer 4, ie the first lacquer layer 4 of the embossing foil in FIG. 1. The intermediate layer 50 corresponds to the background layer 5, ie the second lacquer layer 5 of the embossing foil in FIG Adhesive layer 60 corresponds to adhesive layer 6 of the embossing film in FIG. 1. The laminating films in FIGS. 7 and 8 represent modifications of the laminating film in FIG. 6, in which the background layer corresponds in a similar manner to the background layer in the hot stamping foils in FIGS modified.

The laminating film in FIG. 9 has a layer structure with an order of the layers lying on top of one another, which has been modified with respect to FIGS. 6 to 8. The order of the layers corresponds to the structure of the hot stamping foil in Fig. 5. Here, the layer 70 is an optional background layer.

FIG. 9a shows an embodiment modified from the exemplary embodiment in FIG. 9 with an order of the layers corresponding to the structure of the hot stamping foil in FIG. 5a.

The laminating film in FIG. 10 represents a modification of the laminating film in FIG. 9. In this exemplary embodiment, the overlay film 30 is provided with a hot stamping foil applied thereon. This hot stamping film applied there replaces the layers 31, 50 or 50r, 40, 70 and 60 provided in the laminating film in FIG. 9 with the corresponding layers of the hot stamping foil. In contrast to the embossing foil in FIG. 5, the reflective layer 5r and the laser-sensitive layer 4 are arranged in the reverse order, so that in the case of the laminating foil in FIG. 10, as in the case of the laminating foil of FIG Reflection layer 5r is arranged on the side facing away from the substrate side of the laser-sensitive layer 4.

Consistent with the other illustrated embodiments, the diffraction structure 5b in the laminating film in Fig. 10 is also formed in the adjoining areas of the layers 4 and 5. The lacquer layer 5 is formed here as a transparent layer.

The laminating film in FIG. 10a has a similar structure to the laminating film in FIG. 10. In the exemplary embodiment in FIG. 10a, however, the overlay film 30 is provided with a hot stamping foil applied thereon, which has a similar construction to the hot stamping foil of the exemplary embodiment in FIG. 5a. This hot stamping foil applied to the overlay foil 30 replaces the layers 31, 40, 50, 50r, 40, 70 and 60 provided in the laminating foil in FIG. 9a with the corresponding layers of the hot stamping foil. The laminating film in FIG. 10a has a layer sequence in the following sequence: overlay film 30, adhesive layer 6, optional lacquer layer 5, laser-sensitive layer 4, reflection layer 5r, laser-sensitive layer 4, additional lacquer layer 5c and protective layer 3. The laser-sensitive layers 4 formed on both sides of the reflection layer 5r can be identical, ie the reflection layer 5r is then arranged in this laser-sensitive overall layer. However, the laser-sensitive layers 4 can also be designed differently. The lacquer layer 5 is formed here as a transparent layer or as a light backup layer.

The laminating film in FIG. 10b represents an exemplary embodiment in which a hot embossing film is likewise applied to the overlay film 30. This applied hot stamping foil is of similar design as the foil in FIG. 5. It replaces the layers 31, 40, 50 or 50r, 40, 70 and 60 provided in the laminating foil in FIG. 9a by the layers of the hot stamping foil. The laminating film in FIG. 10b has a layer sequence with the following sequence: overlay film 30, adhesive layer 6, optional lacquer layer 7, laser-sensitive layer 4, reflection layer 5r, additional lacquer layer 5c and protective layer 3. Here, the lacquer layer 7 is a transparent layer or a light backup layer educated.

The laser treatment of the laminating film is carried out in a corresponding manner as described for the transfer film, ie by appropriate successive bleaching of the in the laser-sensitive layer 40 contained pigments or other colorants or by appropriate color changes of the pigments or other colorants.

Claims (19)

1. Plastic body, which is provided in the form of a film, for example, a transfer film, in particular a hot embossing film, or laminating film or which is provided with a film of this type, at least part of the body (4) having in its material composition a colour mixture which is composed of at least three different components, each of the three components being formed as a pigment or as another colorant and can be changed by means of a laser under laser conditions which are specific for the component in each case, that is to say can be changed by bleaching and/or a colour change, preferably can be changed by a colour change on its own, characterized in that it is true of each of the three components that, under the laser conditions specific for one component, the remaining components cannot be changed or cannot be changed substantially, and in that during the laser irradiation, at least one of the components exhibits a colour change.
2. Plastic body according to Claim 1, characterized in that the laser conditions specific for the various components are preferably different with respect to the laser wavelength and, under the laser conditions specific for the respective component, the remaining components cannot be changed or cannot be changed substantially.
3. Plastic body according to Claim 1 or 2, characterized in that, at a point on the plastic body, preferably at least in some regions at each point on the plastic body, a plurality of different components of the colorant mixture, preferably all the different components of the colorant mixture, are arranged in mixed form and the colour at this point is formed by preferably subtractive colour mixing.
4. Plastic body according to one of the preceding planes, characterized in that the component absorbs at the wavelength of the laser light used, in that the component has an absorption maximum at this wavelength, preferably one of a plurality of absorption maxima and preferably its single or its largest absorption maximum.
5. Plastic body according to one of Claims 1 to 4, characterized in that the component absorbs light at the wavelength of the laser light used but the component does not have an absorption maximum at this wavelength, instead this wavelength lies outside the absorption maximum or outside the absorption maxima of the component.
6. Plastic body according to one of the preceding claims, characterized in that the mixture has only three colorant components or more than three colorant components.
7. Plastic body according to one of the preceding claims, characterized in that one bleachable component is a cyan colorant, preferably cyan pigment, and/or in that one bleachable component is a magenta colorant, preferably magenta pigment, and/or in that one bleachable component is a yellow colorant, preferably yellow pigment.
8. Plastic body according to Claim 7, characterized in that the cyan colorant is formed as a colorant that can be bleached only or preferably with red laser light, and/or in that the magenta colorant is formed as a colorant that can be bleached only or preferably with green laser light, and/or in that the yellow colorant is formed as a colorant that can be bleached only or preferably with blue laser light.
9. Method for producing a multicolour image on or in a plastic body according to one of the preceding Claims 1 to 8, characterized in that, in a first step, by means of laser irradiation of a point on the plastic body under laser conditions specific for one of the three components, only one component is changed, and in that, in a second step, by means of laser irradiation of the same point on the body under laser conditions specific for a further of the three components, only this further component is changed.
10. Method according to Claim 9, characterized in that, in a third step, by means of laser irradiation of the same point on the plastic body under laser conditions specific for another further of the three components, only this other further component is changed.
11. Method according to Claim 9 or 10, characterized in that, in an nth step, by means of laser irradiation of the same point on the plastic body under laser conditions specific for an nth further component, only this nth component is changed, n being greater than 3.
12. Method according to one of Claims 9 to 11, characterized in that, as a result of the laser irradiations of this point on the body, all the components are changed.
13. Method according to one of Claims 9 to 12, characterized in that during the laser irradiation, by controlling the laser conditions, in particular the laser intensity and/or the pulse duration and/or irradiation time, the level of bleaching to be achieved is set.
14. Method according to one of Claims 9 to 13, characterized in that the plastic body is laser irradiated successively at a plurality of points.
15. Method according to Claim 9 to 14, characterized in that, as a result of the laser irradiation at this point on the body, a colour is produced which is formed by the colorants or components remaining at this point.
16. Method according to one of Claims 9 to 15, characterized in that a plurality of different components, preferably all the different components, are arranged mixed at one point on the plastic body, and the colour of this point is formed by subtractive colour mixing.
17. Method according to one of Claims 9 to 16, characterized in that the bleachable component used is a cyan colorant, preferably cyan pigment, and/or a magenta colorant, preferably magenta pigment, and/or a yellow colorant, preferably yellow pigment.
18. Method according to Claim 17, characterized in that, in order to bleach the cyan colorant, red laser light is used, and/or in order to bleach the magenta colorant, green laser light is used, and/or in order to bleach the yellow colorant, blue laser light is used.
19. Method according to Claim 17 or 18, characterized in that the colour blue is formed by superimposition, preferably subtractive mixing, of the colorants cyan and magenta, preferably from the colorant mixture having cyan colorant, magenta colorant and yellow colorant by bleaching the yellow colorant;
    and/or
    in that the colour green is formed by superimposition, preferably subtractive mixing, of the colorants cyan and yellow, preferably from the colorant mixture having cyan colorant, magenta colorant and yellow colorant by bleaching the magenta colorant;
    and/or
    in that the colour red is formed by superimposition, preferably subtractive mixing, of the colorants yellow and magenta, preferably from the colorant mixture having magenta colorant, yellow colorant and cyan colorant by bleaching the cyan colorant;
    and/or
    in that black or grey is formed by superimposition, preferably subtractive mixing, of the colorants cyan, magenta and yellow, preferably from the colorant mixture having magenta colorant, yellow colorant and cyan colorant;
    and/or
    in that the colour magenta is formed by the magenta colorant by bleaching the colorants present in the colorant mixture apart from the magenta colorant, preferably from the colorant mixture comprising magenta colorant, yellow colorant and cyan colorant by bleaching the yellow colorant and the cyan colorant;
    and/or
    in that the colour cyan is formed by the cyan colorant by bleaching the remaining colorants present in the colorant mixture apart from the cyan colorant, preferably from the colorant mixture comprising cyan colorant, yellow colorant and magenta colorant by bleaching the magenta colorant and the yellow colorant;
    and/or
    in that the colour yellow is formed by the yellow colorant by bleaching all the colorants present in the colorant mixture apart from the yellow colorant, preferably from the colorant mixture comprising yellow colorant, magenta colorant, and cyan colorant by bleaching the magenta colorant and the cyan colorant.

Images